Frustration with USB Boot device I disabled secure boot and did the f12 and selected USB device. The blue windows logo appears for about 30 seconds, a CMD Window opens up for a split second, a screen flash and then reboots. After the reboot all I get is a black screen, I then have to power off the computer and go back into the Boot selector (F12) to turn Secure Boot back on so I can start the PC normally,